| Summary: | 碩士 === 國立臺灣師範大學 === 機電科技學系 === 101 === A film, with water contact angle over than 150°, is usually categorized as superhydrophobic. Hydrophobic treatments have received much attention on the application potentials of self-cleaning devices, microfluidic systems, and biocompatibility. This study attempts to deposite superhydrophobic films using a low-cost atmospheric plasma process (APP) at the conditions of low temperatures (<150°C) and high deposition rate. The morphology, composition, and physical characteristics of hydrophobic films have been explored. Moreover, a technique, which combines photolithography and lift-off process to pattern the super-hydrophobic film, has been developed for fabricating liquid microlens array (LMLA). Except evaluating the optical performance of the liquid microlens, nano-scaled phosphor powder was also added into the liquid of LMLA for LED packaging, attempt to enhance the light extraction efficiency and white light conversion function.
This study has three major research objectives: (1) Deposit super-hydrophobic films by atmospheric plasma under different self-assembly monomers and processing time to find the optimal depositing parameters. By using clean dry air (CDA) as the process gas, N2 as carrier gas of hexamethyldisilazane (HMDS) monomer. A super-hydrophobic film has been produced, which has water contact angle close to 150, similar as the characteristic of lotus leaves. (2) Evaluate the optical properties, surface morphology, composition of the superhydrophobic film by using the visible light spectroscopy, scanning electron microscopy (SEM), and confocal microscopy measurement etc. The results show that the superhydrophobic film can reach visible light transmittance of 88% and average surface roughness (Ra) of ~500 nm, which is a quite rough surface. (3) Combine lithography, atmospheric plasma treatment, and lift-off process to pattern the hydrophobic film. By the surface tension of the liquid itself, the liquid microlens array would be self-aligned and formed at hydrophilic region. Except the fabrication of LMLA, this study also added nano-scaled phosphor powder into the liquid lens successfully. The initial evaluation of the light extraction and white light conversion for blue LED package combined with a patterned array of phosphor powder has been investigated. Base on this low-cost and unique technique of microlens array production, the application of LED package by microlens array with phosphor powder will be developed in follow-up studies.
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